Coordination chemistry of 2,6-bis(oxazolinyl)-pyridine ruthenium complexes

The cationic complex [mer,trans-Ru(pybox)(PPh3)(2)Cl](+) (1; pybox = 2,6-bi s(oxazolinyl)pyridine has been prepared by the reaction of either Ru(PPh3)( 4)Cl-2 or Ru(PPh3)(3)Cl-2 with stoichiometric amounts of pybox. In solution , 1 is substitutionally labile liberating to some extent PPh3 to give the n eutral complex [mer,cis-Ru(pybox)(PPh3)Cl-2] (2). The isomeric complex [mer , trans-Ru(pybox)(PPh3)Cl-2] (3) has been afforded by the reaction of [Ru(c ymene)Cl-2](2) (cymene) = 4-isopropyl toluene) with 2 equiv. of pybox and P Ph3 in refluxing toluene. Complex 3 is thermodynamically less stable than 2 and is quantitatively converted to 2 at elevated temperature. The X-ray st ructure of 2 . (C2H5)(2)O is reported.